Update samples with latest polymer and Dartium changes

samples/third_party/todomvc/web/app.html

 <!--
 Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 for details. All rights reserved. Use of this source code is governed by a
 BSD-style license that can be found in the LICENSE file.
 -->
 <link rel="import" href="router_options.html">
 <link rel="import" href="todo_row.html">
 <polymer-element name="todo-app">
 <template>
   <section id="todoapp">
     <header id="header">
       <h1 class='title'>todos</h1>
-      <form on-submit="addTodo">
+      <form on-submit="{{addTodo}}">
         <input id="new-todo" placeholder="What needs to be done?" autofocus
-               on-change="addTodo">
+               on-change="{{addTodo}}">
       </form>
     </header>
     <section id="main">
       <input id="toggle-all" type="checkbox" checked="{{app.allChecked}}">
       <label for="toggle-all"></label>
       <ul id="todo-list">
         <template repeat="{{app.visibleTodos}}">
           <li is="todo-row" todo="{{}}"></li>
         </template>
       </ul>
     </section>
     <template if="{{app.todos.length > 0}}">
       <footer id="footer">
         <span id="todo-count"><strong>{{app.remaining}}</strong></span>
         <ul is="router-options" id="filters">
           <li> <a href="#/">All</a> </li>
           <li> <a href="#/active">Active</a> </li>
           <li> <a href="#/completed">Completed</a> </li>
         </ul>
         <template if="{{app.hasCompleteTodos}}">
-          <button id="clear-completed" on-click="clear">
+          <button id="clear-completed" on-click="{{clear}}">
             Clear completed ({{app.doneCount}})
           </button>
         </template>
       </footer>
     </template>
   </section>
   <footer id="info">
     <p>Double-click to edit a todo.</p>
     <p>Credits: the <a href="http://www.dartlang.org">Dart</a> team.</p>
     <p>
       Learn more about
       <a href="https://www.dartlang.org/articles/dart-web-components/">Dart + Web Components</a>
       or
       <a href="https://github.com/dart-lang/web-ui/tree/master/example/todomvc">view the source</a>.
     </p>
     <p>Part of <a href="http://todomvc.com">TodoMVC</a>.</p>
   </footer>
 </template>
 <script type="application/dart" src="app.dart"></script>
 </polymer-element>